(dailyRx News) The image of aimlessly wandering sleepwalkers may conjure up fun images of zombies out of Michael Jackson's Thriller, but sleepwalking can actually indicate or cause serious problems.
A new study has found that about 8.4 million US adults, or 3.6 percent of the population, sleepwalk - and these unconscious nighttime strolls appear to be linked to certain psychiatric conditions, including anxiety and depression.
Maurice Ohayon, MD, a professor of psychiatry and behavioral sciences at Stanford University School of Medicine, led the study to find out how common sleepwalking is because the last statistics on how many people experience it were published about 30 years ago.
When people sleepwalk, they are moving around without actually waking up. Though researchers know sleepwalkers are in a non-REM stage of sleep, they don't fully understand the causes of the condition.
Some theories are that some psychological or psychiatric conditions can cause sleepwalking, or that it is caused by certain medications. The sleep aid drug Ambien, for example, has famously been linked to sleepwalking.
What researchers are certain of is that the activity can have serious negative effects. A sleepwalker can injure himself or others and can suffer from psychiatric problems.
Therefore, Ohayon's team also hoped to establish how associated sleepwalking is with medications and mental disorders.
The researchers identified 19,136 individuals from across 15 states who were representative of the general population in the US. They surveyed these individuals by phone on their mental health, medical history and medication use.
Among the questions asked were whether the respondent sleepwalked and, if so, how often and for how long. Anyone who stated they had not sleepwalked in the past year was asked if they had done so as a child.
Respondents were also asked if they had done anything inappropriate or potentially dangerous while they were asleep, whether anyone in their family sleepwalked and whether they had any other disturbing sleep conditions, such as sleep terrors or violent behaviors during sleep.
Approximately 3.6 percent of respondents said they have sleepwalked at least once in the past year, and one percent said they had done so two more times in a month. When the researchers calculated in responses that included people's childhood sleepwalking, they found that almost one-third (29 percent) of all people sleepwalk at some point in their lives.
The researchers also found that people suffering from Depression were about 3.5 times more likely to sleepwalk than those without depression. A total of 3.1 percent of respondents who had depression reported sleepwalking twice a month or more often, compared to 0.9 percent of those who sleepwalked this frequently but did not have depression.
However, taking medication to treat the depression wouldn't necessarily change these statistics: those taking SSRI antidepressants, a common treatment for depression, were almost three times more likely (2.4 percent) to sleepwalk twice a month compared to those not taking SSRIs (0.9 percent).
Establishing these links, however, is only the beginning of what researchers need to find out.
"There is no doubt an association between nocturnal wanderings and certain conditions, but we don't know the direction of the causality," said Ohayon. "Are the medical conditions provoking sleepwalking, or is it vice versa? Or perhaps it's the treatment that is responsible."
The study appeared in the May 15 issue of Neurology. The research was funded by the National Institutes of Health, the Arrillaga Foundation, the Bing Foundation and an educational grant from Neurocrines Biosciences.
Four of the authors have served on scientific advisory boards or received research support from various pharmaceutical companies.